mirrors/cpython
0
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2024-11-23 01:45:25 +08:00
Code Issues Packages Projects Releases Wiki Activity

gh-125063: marshal: Add version 5, improve documentation (GH-126829)

Browse Source 
* Document that slices can be marshalled
* Deduplicate and organize the list of supported types
  in docs
* Organize the type code list in marshal.c, to make
  it more obvious that this is a versioned format
* Back-fill some historical info

Co-authored-by: Michael Droettboom <mdboom@gmail.com>
This commit is contained in:
Petr Viktorin 2024-11-15 13:48:57 +01:00 committed by GitHub
parent e17486982c
commit d00f7b1b9d
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
7 changed files with 110 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
Doc/c-api/marshal.rst
View File

@ -13,11 +13,12 @@ binary mode.
Numeric values are stored with the least significant byte first.
The module supports two versions of the data format: version 0 is the
historical version, version 1 shares interned strings in the file, and upon
unmarshalling. Version 2 uses a binary format for floating-point numbers.
``Py_MARSHAL_VERSION`` indicates the current file format (currently 2).
The module supports several versions of the data format; see
the :py:mod:`Python module documentation <marshal>` for details.
.. c:macro:: Py_MARSHAL_VERSION
The current format version. See :py:data:`marshal.version`.
.. c:function:: void PyMarshal_WriteLongToFile(long value, FILE *file, int version)

64
Doc/library/marshal.rst
View File

@ -38,23 +38,39 @@ supports a substantially wider range of objects than marshal.
maliciously constructed data. Never unmarshal data received from an
untrusted or unauthenticated source.
There are functions that read/write files as well as functions operating on
bytes-like objects.
.. index:: object; code, code object
Not all Python object types are supported; in general, only objects whose value
is independent from a particular invocation of Python can be written and read by
this module. The following types are supported: booleans, integers, floating-point
numbers, complex numbers, strings, bytes, bytearrays, tuples, lists, sets,
frozensets, dictionaries, and code objects (if *allow_code* is true),
where it should be understood that
tuples, lists, sets, frozensets and dictionaries are only supported as long as
the values contained therein are themselves supported. The
singletons :const:`None`, :const:`Ellipsis` and :exc:`StopIteration` can also be
marshalled and unmarshalled.
For format *version* lower than 3, recursive lists, sets and dictionaries cannot
be written (see below).
this module. The following types are supported:
* Numeric types: :class:`int`, :class:`bool`, :class:`float`, :class:`complex`.
* Strings (:class:`str`) and :class:`bytes`.
:term:`Bytes-like objects <bytes-like object>` like :class:`bytearray` are
marshalled as :class:`!bytes`.
* Containers: :class:`tuple`, :class:`list`, :class:`set`, :class:`frozenset`,
and (since :data:`version` 5), :class:`slice`.
It should be understood that these are supported only if the values contained
therein are themselves supported.
Recursive containers are supported since :data:`version` 3.
* The singletons :const:`None`, :const:`Ellipsis` and :exc:`StopIteration`.
* :class:`code` objects, if *allow_code* is true. See note above about
version dependence.
.. versionchanged:: 3.4
* Added format version 3, which supports marshalling recursive lists, sets
and dictionaries.
* Added format version 4, which supports efficient representations
of short strings.
.. versionchanged:: next
Added format version 5, which allows marshalling slices.
There are functions that read/write files as well as functions operating on
bytes-like objects.
The module defines these functions:
@ -140,11 +156,24 @@ In addition, the following constants are defined:
.. data:: version
Indicates the format that the module uses. Version 0 is the historical
format, version 1 shares interned strings and version 2 uses a binary format
for floating-point numbers.
Version 3 adds support for object instancing and recursion.
The current version is 4.
Indicates the format that the module uses.
Version 0 is the historical first version; subsequent versions
add new features.
Generally, a new version becomes the default when it is introduced.
======= =============== ====================================================
Version Available since New features
======= =============== ====================================================
1 Python 2.4 Sharing interned strings
------- --------------- ----------------------------------------------------
2 Python 2.5 Binary representation of floats
------- --------------- ----------------------------------------------------
3 Python 3.4 Support for object instancing and recursion
------- --------------- ----------------------------------------------------
4 Python 3.4 Efficient representation of short strings
------- --------------- ----------------------------------------------------
5 Python 3.14 Support for :class:`slice` objects
======= =============== ====================================================
.. rubric:: Footnotes
@ -154,4 +183,3 @@ In addition, the following constants are defined:
around in a self-contained form. Strictly speaking, "to marshal" means to
convert some data from internal to external form (in an RPC buffer for instance)
and "unmarshalling" for the reverse process.

2
Include/marshal.h
View File

@ -13,7 +13,7 @@ PyAPI_FUNC(PyObject *) PyMarshal_ReadObjectFromString(const char *,
Py_ssize_t);
PyAPI_FUNC(PyObject *) PyMarshal_WriteObjectToString(PyObject *, int);
#define Py_MARSHAL_VERSION 4
#define Py_MARSHAL_VERSION 5
PyAPI_FUNC(long) PyMarshal_ReadLongFromFile(FILE *);
PyAPI_FUNC(int) PyMarshal_ReadShortFromFile(FILE *);

27
Lib/test/test_marshal.py
View File

@ -28,6 +28,13 @@ class HelperMixin:
finally:
os_helper.unlink(os_helper.TESTFN)
def omit_last_byte(data):
"""return data[:-1]"""
# This file's code is used in CompatibilityTestCase,
# but slices need marshal version 5.
# Avoid the slice literal.
return data[slice(0, -1)]
class IntTestCase(unittest.TestCase, HelperMixin):
def test_ints(self):
# Test a range of Python ints larger than the machine word size.
@ -241,7 +248,8 @@ class BugsTestCase(unittest.TestCase):
def test_patch_873224(self):
self.assertRaises(Exception, marshal.loads, b'0')
self.assertRaises(Exception, marshal.loads, b'f')
self.assertRaises(Exception, marshal.loads, marshal.dumps(2**65)[:-1])
self.assertRaises(Exception, marshal.loads,
omit_last_byte(marshal.dumps(2**65)))
def test_version_argument(self):
# Python 2.4.0 crashes for any call to marshal.dumps(x, y)
@ -594,6 +602,19 @@ class InterningTestCase(unittest.TestCase, HelperMixin):
s2 = sys.intern(s)
self.assertNotEqual(id(s2), id(s))
class SliceTestCase(unittest.TestCase, HelperMixin):
def test_slice(self):
for obj in (
slice(None), slice(1), slice(1, 2), slice(1, 2, 3),
slice({'set'}, ('tuple', {'with': 'dict'}, ), self.helper.__code__)
):
with self.subTest(obj=str(obj)):
self.helper(obj)
for version in range(4):
with self.assertRaises(ValueError):
marshal.dumps(obj, version)
@support.cpython_only
@unittest.skipUnless(_testcapi, 'requires _testcapi')
class CAPI_TestCase(unittest.TestCase, HelperMixin):
@ -654,7 +675,7 @@ class CAPI_TestCase(unittest.TestCase, HelperMixin):
self.assertEqual(r, obj)
with open(os_helper.TESTFN, 'wb') as f:
f.write(data[:1])
f.write(omit_last_byte(data))
with self.assertRaises(EOFError):
_testcapi.pymarshal_read_last_object_from_file(os_helper.TESTFN)
os_helper.unlink(os_helper.TESTFN)
@ -671,7 +692,7 @@ class CAPI_TestCase(unittest.TestCase, HelperMixin):
self.assertEqual(p, len(data))
with open(os_helper.TESTFN, 'wb') as f:
f.write(data[:1])
f.write(omit_last_byte(data))
with self.assertRaises(EOFError):
_testcapi.pymarshal_read_object_from_file(os_helper.TESTFN)
os_helper.unlink(os_helper.TESTFN)

2
Misc/NEWS.d/next/Library/2024-11-14-13-16-20.gh-issue-125063.kJ-WnH.rst Normal file
View File

@ -0,0 +1,2 @@
:mod:`marshal` now supports :class:`slice` objects. The marshal format
version was increased to 5.

1
Programs/_freeze_module.c
View File

@ -121,6 +121,7 @@ compile_and_marshal(const char *name, const char *text)
return NULL;
}
assert(Py_MARSHAL_VERSION >= 5);
PyObject *marshalled = PyMarshal_WriteObjectToString(code, Py_MARSHAL_VERSION);
Py_CLEAR(code);
if (marshalled == NULL) {

46
Python/marshal.c
View File

@ -50,41 +50,52 @@ module marshal
# define MAX_MARSHAL_STACK_DEPTH 2000
#endif
/* Supported types */
#define TYPE_NULL '0'
#define TYPE_NONE 'N'
#define TYPE_FALSE 'F'
#define TYPE_TRUE 'T'
#define TYPE_STOPITER 'S'
#define TYPE_ELLIPSIS '.'
#define TYPE_INT 'i'
/* TYPE_INT64 is not generated anymore.
Supported for backward compatibility only. */
#define TYPE_INT64 'I'
#define TYPE_FLOAT 'f'
#define TYPE_BINARY_FLOAT 'g'
#define TYPE_COMPLEX 'x'
#define TYPE_BINARY_COMPLEX 'y'
#define TYPE_LONG 'l'
#define TYPE_STRING 's'
#define TYPE_INTERNED 't'
#define TYPE_REF 'r'
#define TYPE_TUPLE '('
#define TYPE_BINARY_FLOAT 'g' // Version 0 uses TYPE_FLOAT instead.
#define TYPE_BINARY_COMPLEX 'y' // Version 0 uses TYPE_COMPLEX instead.
#define TYPE_LONG 'l' // See also TYPE_INT.
#define TYPE_STRING 's' // Bytes. (Name comes from Python 2.)
#define TYPE_TUPLE '(' // See also TYPE_SMALL_TUPLE.
#define TYPE_LIST '['
#define TYPE_DICT '{'
#define TYPE_CODE 'c'
#define TYPE_UNICODE 'u'
#define TYPE_UNKNOWN '?'
// added in version 2:
#define TYPE_SET '<'
#define TYPE_FROZENSET '>'
// added in version 5:
#define TYPE_SLICE ':'
#define FLAG_REF '\x80' /* with a type, add obj to index */
// Remember to update the version and documentation when adding new types.
/* Special cases for unicode strings (added in version 4) */
#define TYPE_INTERNED 't' // Version 1+
#define TYPE_ASCII 'a'
#define TYPE_ASCII_INTERNED 'A'
#define TYPE_SMALL_TUPLE ')'
#define TYPE_SHORT_ASCII 'z'
#define TYPE_SHORT_ASCII_INTERNED 'Z'
/* Special cases for small objects */
#define TYPE_INT 'i' // All versions. 32-bit encoding.
#define TYPE_SMALL_TUPLE ')' // Version 4+
/* Supported for backwards compatibility */
#define TYPE_COMPLEX 'x' // Generated for version 0 only.
#define TYPE_FLOAT 'f' // Generated for version 0 only.
#define TYPE_INT64 'I' // Not generated any more.
/* References (added in version 3) */
#define TYPE_REF 'r'
#define FLAG_REF '\x80' /* with a type, add obj to index */
// Error codes:
#define WFERR_OK 0
#define WFERR_UNMARSHALLABLE 1
#define WFERR_NESTEDTOODEEP 2
@ -615,6 +626,11 @@ w_complex_object(PyObject *v, char flag, WFILE *p)
PyBuffer_Release(&view);
}
else if (PySlice_Check(v)) {
if (p->version < 5) {
w_byte(TYPE_UNKNOWN, p);
p->error = WFERR_UNMARSHALLABLE;
return;
}
PySliceObject *slice = (PySliceObject *)v;
W_TYPE(TYPE_SLICE, p);
w_object(slice->start, p);